Floating and lifting bridge



A. BLONDEL.

FLOATING AND LIFT'ING BRIDGE.

APPLICATION FILED MAY27, 1919.

1,367,1 15. Patented Feb. 1,1921.

Inventor: fl% M By his Altar-nay;

NT. OFFICE.

ALFRED BLONDEL, OF TOURNAI, BELGIUM.

FLOATING AND LIFTING BRIDGE.

isemis.

Specification of Letters Patent.

Application filed May 27, 1919. Serial No. 300,153.

To all whom it may concern."

Be it known that I, ALFRED BLONDEL, a subject of the King of Belgium, residing at Tournai, in the Kingdom of Belgium, have invented certain new and useful Improvements in Floating and Lifting Bridges, of which the following is a specification.

My invention relates to lmprovements n lloatin and lifting bridges of that class 111 which bala-ncing floats immersed in watertight shafts are cooperating with auxiliary means adaptedto secure the complemental motive power which is necessary to operate the bridge, that is to say, to effect its ascent and descent.

One object of my invention is to provide for a greater security than hitherto attained in the operation of the bridge.

Another object of my invention is to re duce the costs of construction of bridges of this class, and a further object is to provide simple and reliable means for the con trol. of the tightness of the floats.

'With these objects in view, my invention essentially consists in special combinations and arrangements of parts which will be hereinafter fully described and pointed out in the appended claims.

Referring to the annexed drawing:

Figure 1 shows diagrammatically partly in section a lifting bridge constructed according to my invention,

Fig. 2 is a top view of the bridge corre sponding to Fig. 1. i p

In these figures a is the movable part ofa lifting bridge, 5 the floats cooperating with said movable part and which are immersed in watenrooms p. y

In lifting bridges of this class as hitherto eonstructecil, the floats l) were generally used to balance more or less the weight of the movable part of the bridge, auxiliary means (such as a float having variable buoyancy or any other suitable motive power) being used for raising and lowering the bridge.

According to my invention, on the contrary, the floats '1') which are completely immersed in the water contained in suitable rooms p, are dimensioned in such a manner. as to possess an excess of lifting power or buoyancy, having consequently the tendency to hold the movable part of the bridge in its uppermost position, whereas the auxiliary means secures the necessary force to retain the movable part in its lowest position.

The floats b which are preferably elliptical in shape, instead of being arranged vertically in water-tight shafts as is generally the case, are arranged horizontally in the water-rooms p extending longitudinally on both sides of theriver. These water-rooms can be constructed very easily by dredging the bed of the river so as to provide for the necessary depth and then constructing walls 9 in a well known manner.

'1 is the auxiliary motor such as an electric-motor cooperating with cables 8 which are suitably guided and attached to the walls of the water roomsp or to any other points of the river-bank; the pull of these cables 8 which is produced for example by the rotation of a drum to which the cables are attached at one end and which is driven by the motor, balances the excess of buoyancy of the floats Z) and holds the movable part a of the bridge in its lowest position in which it rests upon suitable bases orbeds at the up per ends of the wharf walls.

The floats b, which necessarily possess great dimensions can be connected to the movable part of the bridge by the aid of tubes t in which a ladder to can be arranged to enable the inspection of the floats. Further in order to facilitate the control of the tightness of the floats, these floats are preferably connected by a pipe to a pump, driven by the auxiliary motor r or by any other suitable motor, said pump mamtammg n the floats a given pressure such as for instance a pressure of about two atmospheres. In this case, however, the tubes t must be evidently closed at their upper part and the floats can be providedwith a safety-valve preventing any excess of ressure. In these conditions any defect o tightness of the floats is immediately disclosed either on account of the fall of pressure or on account of the ascent of air bubbles to the surface of the water. i

In order to avoid with certainty any wedging of the floats against the walls of the rooms p, the floats can be provided at the place of their greatest diameter, with roll? ers '0 adapted to roll. along said walls in case of contact; this arrangement can be advantageously combined with the use of oscillating floats that is to say of floats pivotally connected to the movable part of the bridge This construction is particularly suitable in lifting bridges, the movable part of which is pivotally mounted at one end on the wharf wall and in which the floats necessarily move Patented Feb. 1, 1921.

to some extent in a horizontal direction during the operation of the bridge, the rollers contacting alternately with only one'of the walls of the water-rooms in which the floats are immersed.

Independently of the great security of operation of a lifting bridge constructed as described, it is to'be noted, that in case of failure of the motor, the bridge remains in its uppermost position without interfering with the'traflie on the river or channel.

Another important; advantage of the construction as described consists in the fact that the digging of shafts of great depth can bedispensed with, this operation being replaced by a simpledredging operation.

With regard to the operation of the bridge it will be observed that the lifting bridge, constructed according to my invention, is like a kind of captive bridge (by analogy witha captive balloon) and that the floats, if they are emerging from the water, act as a brake, the speed of ascent of the movable part of the bridge which is maximum at the beginning'of the ascent, being reduced gradually in proportion to the degree of emersion of the floats until a state of equilibrium corresponding to the uppermost position of the bridge will be attained.

lVhat I claim is:

1. In a lifting bridge, in combination with the movable part of the bridge and piers, floats cooperating with said movable part, the buoyancy of said floats being greater than that necessary to balance the weight of the movable part and auxiliarymeans connected between the movable part of the bridge and the piers and operative to retain the movable part of the bridge in its lowest position against the action of the floats.

2. Ina lifting bridge in combination with the movable part of the bridge and piers, floats cooperating with said movable part, the buoyancy of' said floats being greater than that necessary to balance the weight ofthe movable part, water-rooms arranged on both sides of the river, and in which the floats are immersed, the said floats being horizontally arranged-in said rooms, an auxiliary motor, and means controlled by the motor and connected between the piers and movable part of the bridge for lowering the said movable part against the action of the floats.

3. In a lifting bridge, in combination with the movable part of the bridge, a float supporting the movable part of the bridge at each end, the buoyancy of said floats being greater than that necessary to balance the weight of the movable part of the bridge, a water-room on each side of the river, the floats being immersed and horizontally ar ranged in said water-rooms, means connecting the floats to the movable part of the bridge, the said means giving access to the floats, an auxiliary motor mounted on the movable part of the bridge and cables coniected at one end to said motor and at the other end to points of the river bank, whercby the movable part of the bridge may be lowered and held in its lowest position by the pull of the motor on the cables.

4. In a lifting bridge, the combination with the mo "able part of the bridge, a plurality of floats supporting the movable part of the bridge, the total buoyancy of said floats being greater than that necessary to balance the weight of the movable part of the bridge, water rooms arranged on both sides of the river and in which the floats are immersed, the said floats being horizontally arranged in the said water-rooms, tubes connecting the floats to the movable part of the bridge, a ladder in each of said tubes, an auxiliary motor mounted on the movable part of the bridge, cables connected at one end to said motor and at the other end to points of the river-bank, whereby the mow able part of the bridge is held in its lowest position by the pull of the motor on the cables, and means for controlling the tightness of the floats.

In testimony whereof I have allixed my signature in presence of two witnesses.

ALFRED BLONDEL.

Witnesses ROBINSON RILEY.

PETER PETERSEN. 

